`|[cos(x+y),sin(x+y),-cos(x+y)],[sin(x-y),cos(x-y),sin(x-y)],[sin2x,0,sin2y]|=sin2(x+y)`

cos (x + y), sin (x + y), - cos (x + y) sin (xy), cos (xy), sin (xy) sin2x, 0, sin2y] | = sin2 (x + y)

|[cos(x+y),-sin(x+y),cos2y],[sin x,cos x,sin y],[-cos x,sin x,-cos y]|=

Prove that (i) 2 cos x cos y=cos (x+y)+cos (x-y) (ii) -2 . sin x sin y=cos (x+y)-cos (x-y) (iii) 2 sin x cos y=sin (x+y)+sin (x-y) (iv) 2 cos x sin y=sin (x+y)-sin (x-y)

Show that (i) cos x+cos y=2 cos (x+y)/(2) cos (x-y)/(2) (ii) cos x-cos y=-2 sin (x+y)/(2) sin (x-y)/(2) (iii) sin x+sin y=2 sin (dot(x)+y)/(2) cos (x-y)/(2) (iv) sin x-sin y=2 cos (x+y)/(2) sin (x-y)/(2)

(sin 2x - sin 2y)/(cos 2y-cos 2x) = cot (x+y)

What is the value of {sin (x+y) -2 sin x+ sin(x-y)} /[cos (x-y) +cos (x+ y)-2 cos x] xx [(sin 10x- sin 8x)/ (cos-10x + cos 8x)] ? {[sin (x+y] -2 sin x+ sin(x-y)}//[cos (x-y) +cos (x+ y)-2 cos x]} xx [(sin 10x-sin 8x)//(cos10x + cos 8x)] का मान क्या है?

Prove that |(1,x,y),(0, sin x, sin y),(0, cos x,cos y)|= sin (x-y)

56.The value of cos^(2)x+cos^(2)y-2cos x cos y cos(x+y) is (A) sin(x+y) (B) sin^(2)(x+y) (C) sin(x+y) (D) sin(x+y)

(sin x - sin y)/( cos x + cos y) = tan ""(x-y)/(2)

(sin x - sin y)/( cos x + cos y) = tan ""(x-y)/(2)